Hydrogels having microscopic structures were synthesized by a photolithographic method. First a photoreactive pH or thermo-sensitive polymer was synthesized by chemical coupling of poly(acrylic acid) and poly(N-isopropylacrylamide-co-acrylic acid) with azidoaniline. Sub-sequently, the polymer was coated on a polystyrene plate or a glass plate and the coated plate was photo-irradiated through photomasks having prescribed patterns. pH or thermo-responsive microgels whose structures corresponded to the photomask patterns were constructed. They rapidly swelled and contracted by changing pH or temperature. The pH or temperature-induced structural change was reversible.
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